The invention relates to an overhead cable transport installation, in particular a gondola lift or a chairlift, comprising a closed-loop overhead haulage-track cable extending between two end stations and running in a closed circuit. A plurality of carriages each supporting a gondola or a chair and having a detachable grip are able to be coupled to the cable for travel along the circuit, detached from the cable upon entering a station, and recoupled to the cable upon leaving the station. Each grip has a pair of jaws for clamping the cable. In the station, the detached carriages run on a transfer rail before being recoupled on the cable. A coupling rail section at the exit of the transfer rail, extends substantially parallel to the cable so that the cable is inserted between the pair of jaws. The coupling rail section is equipped with a grip actuating device for closing the jaws and coupling the carriage to the cable before the carriage leaves the coupling rail section.
The U.S. Pat. No. 4,699,064 describes an installation of the above-described type. In such known installations an assortment of safety sensors are generally mounted on or about various mechanical and electrical devices so as to report on various operating conditions and to cause the stopping of the installation if necessary. Sensing switches are for instance placed adjacent the grip run in the station to determine the position of the grip, and to stop the installation when the jaws are not closed at the exit of the coupling rail section. The power supply to the electrical motor of the installation is interrupted but the stopping is not immediate and the carriage further moves a given distance. If the grip is open or does not bear on the cable, the carriage falls down at the end of the transfer rail.
The object of the present invention is to improve operational safety of an installation and to prevent the falling down of a gondola or of a chair.